Voice encoders are commonly used to compress speech data for storage or transmission over a channel. Compression enables an increase in the number of communication channels available to a digital communication system by decreasing the bandwidth allocated to each channel.
A variety of speech compression algorithms are available to encode speech signals. For example, one popular encoding technique is code excited linear predictive (CELP) coding, which has proven effective for bit rates in a range of 4-16 kilobits/second.